Same-day ACH debits rolled out last month, a year after same-day credits, cutting processing time for these payments from a couple of days to a few hours — but for many emerging use cases, that’s not fast enough. And debit is filling the void.

For the last two years, the central bank has allowed the private sector to drive a process aimed at modernizing the nation's payments system. Now the Fed will have to determine what its own role will be.

A group of credit unions is working to get a jump how real-time payment processing fits into their world, even as the broader payments industry wrestles with questions about the technology's implementation.